{{short description|Unit of sound absorption}} {{Other uses|Sabin (disambiguation){{!}}Sabin}} thumb|400px|The sabin
In acoustics, the '''sabin''' (or more precisely the '''square meter or foot sabin''') is a unit of sound absorption, used for expressing the total effective absorption for the interior of a room. Sound absorption can be expressed in terms of the percentage of energy absorbed compared with the percentage reflected. It can also be expressed as a coefficient, with a value of 1.00 representing a material which absorbs 100% of the energy, and a value of 0.00 meaning all the sound is reflected.{{sfn|Moore|1979|p=35}}
The concept of a unit for absorption was first suggested by American physicist Wallace Clement Sabine, the founder of the field of architectural acoustics. He defined the "open-window unit" as the absorption of {{convert|1|sqfoot|m2}} of open window.{{sfn|Moore|1979|p=35}} The unit was renamed the ''sabin'' after Sabine, and it is now defined as "the absorption due to unit area of a totally absorbent surface".{{sfn|Moore|1979|p=35}}
Sabins may be calculated with either imperial or metric units. One square foot of 100% absorbing material has a value of one imperial sabin, and 1 square metre of 100% absorbing material has a value of one metric sabin.
The total absorption {{mvar|A}} in metric sabins for a room containing many types of surface is given by <math display=block>A = S_1 \alpha_1 + S_2 \alpha_2 + \ldots + S_n \alpha_n = \sum S_i \alpha_i ,</math> where {{math|''S''<sub>1</sub>, ''S''<sub>2</sub>, ..., ''S<sub>n</sub>''}} are the areas of the surfaces in the room (in m<sup>2</sup>), and {{math|''α''<sub>1</sub>, ''α''<sub>2</sub>, ..., ''α<sub>n</sub>''}} are the absorption coefficients of the surfaces.
Sabins are used in calculating the reverberation time of concert halls, lecture theatres, and recording studios.{{sfn|Davis|Davis|1975|p=168}}
== References == {{reflist}}
== Sources == * {{cite book |last1=Davis |first1=Don |last2=Davis |first2=Caroline |title=Sound System Engineering |edition=2nd |date=1975 |page=|publisher=H. W. Sams |location=Indianapolis |isbn=978-0-672-21156-0 |url=https://books.google.com/books?id=aaLcAwAAQBAJ&q=davis+Sound+System+Engineering }} * {{cite book |last1=Moore |first1=John Edwin |title=Design for Good Acoustics and Noise Control |date=1979 |publisher=Macmillan |location=London |isbn=978-03332-4-293-3 |url=https://books.google.com/books?id=RD5dDwAAQBAJ}}
== External links == * [https://www.controlnoise.com/support-tools/about-sound-waves/understanding-sabins/ Understanding sabins] from NetWell Noise Control
Category:Units of measurement Category:Sound measurements